The Implicit Relational Assessment Procedure (IRAP) is a recently developed experimental task that was designed to examine implicit beliefs or attitudes. Experiment 1 presented the samples “More Likeable” and “Less Likeable” and the target stimuli Irish-Scottish, Scottish-American, American-African, and vice-a-versa (e.g., Scottish-Irish). Response latencies obtained from Irish participants on the IRAP showed a strong preference for Irish over Scottish and American over African. In contrast, responses to explicit Likert measures diverged from the IRAP performance in indicating, Irish equally likeable to Scottish and African more likeable than American. Using a similar IRAP, Experiment 2 showed that participants from the USA showed strong implicit preferences for American over Irish, Irish over Scottish, and Scottish over African; the explicit Likert measures again diverged from the IRAP, showing a preference for Irish over American with no significant differences among American, Scottish, and African. The IRAP data in both experiments were predicted on the basis of perceived social similarity; the responses to the Likert measures may have been influenced by “social desirability”. The findings provide preliminary support for the IRAP as a possibly useful measure of implicit beliefs.